Cholesterol Journal Articles

Record 6741 to 6760

High cholesterol may protect against infections and atherosclerosis
Ravnskov, U. (2003), Qjm 96(12): 927-34.

High correlation but lack of agreement between direct high-performance gel chromatography analysis and conventional indirect methods for determining lipoprotein cholesterol
Krause, B. R., N. J. Schork, et al. (1996), Clin Chem 42(12): 1996-2001.
Abstract: Low-density lipoprotein-cholesterol (LDL-C) is currently estimated clinically by using the Friedewald formula, when plasma triglycerides are < 4000 mg/L, or as the difference between infranatant and high-density lipoprotein-cholesterol (HDL-C) values after ultracentrifugation of plasma at native density, when plasma triglycerides are > or = 4000 mg/L (beta quantification). HDL-C is measured by selective precipitation of apolipoprotein B-containing lipoproteins from whole plasma or from the density > 1.006 kg/L infranatant. We compared these conventional methods for LDL-C and HDL-C with "high-performance" gel chromatography (HPGC), a method that directly and simultaneously measures both LDL-C and HDL-C in a single, microliter volume of plasma. Not surprisingly, we found that the results by all these methods were highly correlated. However, LDL-C values were significantly higher and HDL-C values significantly lower by the direct HPGC method than by the conventional methods (paired t-test). In addition, both Bland-Altman plots and concordance correlation analyses indicated lack of agreement between the methods' results in the majority of patients' subgroups.

High density- and beta-lipoprotein screening for risk of coronary artery disease in the context of new findings on reverse cholesterol transport
Levinson, S. S. (2002), Ann Clin Lab Sci 32(2): 123-36.
Abstract: This article considers how high density lipoproteins (HDL) act as anti-arteriosclerotic agents, examines the usefulness of HDL indexes alone and in conjunction with other markers of coronary artery disease (CAD), and discusses how HDL markers compare with what one might expect from known metabolic mechanisms. This is accomplished by: (i) an overview of mechanisms associated with CAD, especially new findings regarding reverse cholesterol transport; (ii) a brief review of the clinical literature on biochemical markers for automated use; and (iii) analysis of data for persons with or without angiographically documented CAD. Based on these considerations, the ratio of optimized apo A-I/apo B appears superior to lipoprotein lipid markers for predicting the risk of CAD. Yet the ratio shows poor diagnostic accuracy by itself; it yields poorer diagnostic accuracy than would be expected from assessing the metabolic pathways. Discrimination is improved by using the ratio in conjunction with risk factors defined by the National Cholesterol Education Program (NCEP). Based on receiver-operator characteristic (ROC) curve data, this approach increases the accuracy by 13-14% above that obtained with current lipid markers; it improves discrimination more than the use of inflammatory markers. Apolipoprotein testing is better related to the mechanisms of cholesterol transport, is widely available, and requires only two tests, compared to three, to improve discrimination. However, inclusion of inflammatory markers may need to be considered in the future, when more information is available about their functions and clinical value.

High density lipoprotein (HDL) particle uptake mediated by scavenger receptor class B type 1 results in selective sorting of HDL cholesterol from protein and polarized cholesterol secretion
Silver, D. L., N. Wang, et al. (2001), J Biol Chem 276(27): 25287-93.
Abstract: High density lipoprotein (HDL) mediates reverse transport of cholesterol from atheroma foam cells to the liver, but the mechanisms of hepatic uptake and trafficking of HDL particles are poorly understood. In contrast to its accepted role as a cell surface receptor, scavenger receptor class B type 1 (SR-BI) is shown to be an endocytic receptor that mediates HDL particle uptake and recycling, but not degradation, in both transfected Chinese hamster ovary cells and hepatocytes. Confocal microscopy of polarized primary hepatocytes shows that HDL particles enter both the endocytic recycling compartment and the apical canalicular region paralleling the movement of SR-BI. In polarized epithelial cells (Madin-Darby canine kidney) expressing SR-BI, HDL protein and cholesterol undergo selective sorting with recycling of HDL protein from the basolateral membrane and secretion of HDL-derived cholesterol through the apical membrane. Thus, HDL particles, internalized via SR-BI, undergo a novel process of selective transcytosis, leading to polarized cholesterol transport. A distinct process not mediated by SR-BI is involved in uptake and degradation of apoE-free HDL in hepatocytes.

High density lipoprotein apolipoproteins mediate removal of sterol from intracellular pools but not from plasma membranes of cholesterol-loaded fibroblasts
Oram, J. F., A. J. Mendez, et al. (1991), Arterioscler Thromb 11(2): 403-14.
Abstract: Cultured cells possess high-affinity binding sites (receptors) for high density lipoprotein (HDL) that appear to mediate removal of excess intracellular cholesterol from cells. To examine the role of intact HDL apoproteins in receptor-mediated cholesterol removal, HDL3 apoproteins were digested with the proteolytic enzymes trypsin and pronase, and the residual particles were used in sterol efflux experiments. Protease treatment abolished the interaction of HDL3 with the 110-kd cell membrane protein postulated to represent the HDL receptor molecule, indicating that this interaction is mediated by HDL apoproteins rather than lipids. Compared with native HDL3 protease-modified HDL3 had a markedly reduced ability to selectively remove sterol from intracellular pools, even though modified particles promoted greater cholesterol efflux from the plasma membrane than did native particles. These results indicate that whereas sterol efflux from plasma membranes is mediated by HDL lipids, removal of excess intracellular sterol from cells is mediated by HDL apoproteins. These findings are consistent with the hypothesis that receptor binding of HDL apoproteins stimulates translocation of excess intracellular sterol to the cell surface where it becomes accessible for removal by HDL or other lipid-rich acceptor particles.

High density lipoprotein cholesterol and the risk of stroke in elderly men: the Honolulu heart program
Curb, J. D., R. D. Abbott, et al. (2004), Am J Epidemiol 160(2): 150-7.
Abstract: High density lipoprotein (HDL) cholesterol has been inversely associated with coronary heart disease. Associations with stroke are less clear, particularly among the elderly. In this study, the authors examined the relation between HDL cholesterol levels and the risk of stroke in elderly men. Levels of HDL cholesterol were measured in 2,444 Honolulu Heart Program men aged 71-93 years at the 1991-1993 examinations. The participants, who were free of prevalent stroke, coronary heart disease, and cancer at baseline, were followed to the end of 1998 for thromboembolic and hemorrhagic stroke. While HDL cholesterol was unrelated to hemorrhagic events, incidence of thromboembolic stroke declined consistently with increasing HDL cholesterol level (p = 0.003). There was a nearly threefold excess of thromboembolic stroke in men with low HDL cholesterol levels (<1.0 mmol/liter (<40 mg/dl)) compared with men with high levels (> or =1.6 mmol/liter (> or =60 mg/dl)) (10.6/1,000 person-years vs. 3.6/1,000 person-years; p = 0.001). Adjustment for other risk factors had little effect on these findings, although associations appeared strongest in elderly men with "desirable" total cholesterol levels, hypertension, or diabetes mellitus. These findings suggest that HDL cholesterol level is inversely related to the risk of thromboembolic stroke in elderly men. Whether HDL cholesterol alters the effect of other factors on stroke risk in elderly men warrants further study.

High density lipoprotein cholesterol and total cholesterol in children with asthma and allergic rhinitis
Shenoi, A., L. Kumar, et al. (1992), Acta Paediatr 81(2): 150-2.
Abstract: Serum high density lipoprotein cholesterol and total cholesterol were studied in 15 children with allergic rhinitis, 45 asymptomatic asthmatic children and 16 children with acute asthmatic attacks. The latter were also studied in their asymptomatic phase. Two control groups of children with minor anatomical defects and those with acute pneumonia with respiratory distress were also studied. The serum concentrations of high density lipoprotein cholesterol were significantly higher (p less than 0.001) and those of total cholesterol lower (p less than 0.001) in children with respiratory allergy when compared to controls. The concentration of high density lipoprotein cholesterol increased and that of total cholesterol decreased during acute asthma.

High density lipoprotein cholesterol and triglycerides as markers of angiographically assessed coronary artery disease
Nikkila, M., T. Koivula, et al. (1990), Br Heart J 63(2): 78-81.
Abstract: Serum triglycerides, high density lipoprotein (HDL) cholesterol, and total cholesterol were measured in 698 patients examined by angiography. The ratio of HDL cholesterol to total cholesterol was significantly lower in patients with single, double, and triple vessel disease than in patients without disease. The serum concentration of triglyceride was significantly higher in patients with single, double, and triple vessel disease than in those without coronary artery disease. Similar proportion of patients with coronary artery disease and without had serum cholesterol concentrations of greater than or equal to 6.5 mmol/l, but total cholesterol was significantly higher in patients with single, double, and triple vessel disease than in those without. HDL cholesterol (less than 1.0 mmol/l), triglycerides (greater than 2.0 mmol/l), and the ratio of HDL cholesterol to total cholesterol (less than 0.20) were significantly better than total cholesterol as indicators of coronary risk.

High density lipoprotein cholesterol as a mechanistic probe for the side chain cleavage reaction
Takeshima, M. and T. Hara (1991), Biochem Biophys Res Commun 179(1): 161-9.
Abstract: Cholesterol side chain cleavage reaction catalyzed by purified cytochrome P-450scc was stimulated 4-5 fold when cholesterol in rat high density lipoprotein was used as a substrate as compared to the case where cholesterol plus 0.1% Emulgen 911 was used. In the case of the cholesterol-Emulgen system, the Vmax value of activity was not obtained even when a 20 times molar excess of adrenodoxin over the cytochrome was used. However, in the case of the lipoprotein, a 2-3 times molar excess of adrenodoxin over the cytochrome was enough to obtain the half value of Vmax. HPLC gel filtration experiments showed that the three enzymes were eluted from the column as a complex regardless of adding the lipoprotein as judged by the activity and the blotting analysis. However, the activity with the lipoprotein was detected significantly earlier than that in the absence. These and other lines of evidence suggest that the lipoprotein vesicles promote a complex formation among the three enzyme components and serve as a probe for emphasizing a significance of a cluster mechanism in the reaction.

High density lipoprotein cholesterol as a predictor of cardiovascular disease mortality in men and women: the follow-up study of the Lipid Research Clinics Prevalence Study
Jacobs, D. R., Jr., I. L. Mebane, et al. (1990), Am J Epidemiol 131(1): 32-47.
Abstract: With data from the Lipid Research Clinics Prevalence Study used as a baseline, an average of 8.4 years of mortality follow-up has been completed for 8,825 male and female participants who were at least 30 years of age at the time of the study. The participants were examined at 10 North American sites during 1972-1976. Univariate findings for high density lipoprotein (HDL) cholesterol in the 7,569 persons initially free of coronary heart disease indicate an inverse relation with cardiovascular disease mortality for men and women. Controlling for age, low density lipoprotein (LDL) cholesterol, triglycerides, body mass index, systolic blood pressure, and smoking, multivariate analysis results indicate inverse relations between HDL cholesterol and cardiovascular disease mortality. In men, the cardiovascular disease mortality rate ratio for HDL cholesterol increments of 10 mg/dl was similar to the cardiovascular disease mortality rate ratio for LDL cholesterol increments of 30 mg/dl. In women, HDL cholesterol is more closely related to cardiovascular disease than is LDL cholesterol. HDL cholesterol is inversely related to both coronary heart disease and other cardiovascular disease mortality in both sexes, though the relation of HDL cholesterol with coronary heart disease mortality in women approached statistical significance only for the combined end point of suspect and definite cases. No relation was observed in either sex group between HDL cholesterol and noncardiovascular disease mortality. This study, only the second large prospective study evaluating the role of HDL cholesterol in women, confirms both the importance and the independence in both men and women of HDL cholesterol in the epidemiology of coronary heart disease and other cardiovascular disease mortality.

High density lipoprotein cholesterol concentration as a predictor of coronary heart disease in West Indian men
Miller, G. J., G. L. Beckles, et al. (1990), J Epidemiol Community Health 44(2): 136-8.
Abstract: STUDY OBJECTIVE--The aim of the study was to determine whether the inverse association between high density lipoprotein cholesterol concentration and risk of coronary heart disease described in people of European stock was also present in other racial groups. DESIGN--The study was a prospective population survey. Cardiovascular risk factors were examined, including fasting serum lipid estimation (obtained at recruitment). SETTING--This was a community based study within a defined survey area in Trinidad. PARTICIPANTS--All men aged between 35 and 69 years within the survey area were identified and followed between 1977 and 1986. Analysis was confined to those of African, Asian Indian, and mixed descent who were free of coronary heart disease at entry (n = 960, 69% of age eligible men in the survey population). MEASUREMENTS AND MAIN RESULTS--64 men developed coronary heart disease during the study period. A strong inverse curvilinear relation was found between high density lipoprotein cholesterol and coronary heart disease incidence (p less than 0.005), independent of age or other relevant characteristics including low density lipoprotein cholesterol. CONCLUSIONS--A low serum concentration of high density lipoprotein cholesterol is a risk factor for coronary heart disease in non-whites as well as in whites.

High density lipoprotein cholesterol following anaerobic swimming in trained swimmers
Ohkuwa, T. and H. Itoh (1993), J Sports Med Phys Fitness 33(2): 200-2.
Abstract: HDL-C, LDL-C, total cholesterol and glycerol were determined in venous blood of 10 male trained swimmers at rest and following 100-m anaerobic swimming. When compared to rest levels, the peak HDL-C and glycerol concentrations were significantly enhanced following anaerobic swim test (p < 0.01). However, peak LDL-C and total cholesterol after anaerobic swim were not significantly increased compared with the rest level. The present data demonstrated that the anaerobic swimming induces an increase in HDL-C metabolism, suggesting that the anaerobic exercise per se was one reason for the elevated HDL-C levels.

High density lipoprotein cholesterol in individuals with spinal cord injury: the potential role of physical activity
Washburn, R. A. and S. F. Figoni (1999), Spinal Cord 37(10): 685-95.
Abstract: STUDY DESIGN/METHODS: Literature review. Papers were selected from a literature search of both the Medline and Current Contents data bases and through extensive cross checking of references from the author's personal files. OBJECTIVES: To evaluate the evidence for a reduced level of HDL-C in individuals with spinal cord injury and to discuss physiologic and behavioral factors that may be responsible for the observed reduction, with emphasis on the role of physical activity. RESULTS/CONCLUSIONS: The evidence presented suggests that HDL-C may be lower in persons with SCI; however, the available data should be interpreted cautiously due to lack of control for important confounding factors such as smoking, alcohol consumption and physical activity. Results suggest a potential association between increased physical activity and increased HDL-C in persons with SCI. However, the mode, frequency, intensity and duration of activity and the physiologic mechanism responsible for this association have yet to be clearly elucidated.

High density lipoprotein cholesterol increases with living altitude
Dominguez Coello, S., A. Cabrera De Leon, et al. (2000), Int J Epidemiol 29(1): 65-70.
Abstract: BACKGROUND: The relationship between high density lipoprotein cholesterol (HDL) serum level and the altitude at which people live is controversial. METHODS: A cross-sectional study was carried out in the adult population (30-64 years) of the Island of El Hierro (Canary Islands, Spain). In all, 594 individuals representative of the El Hierro population for gender, age, district and the altitude at which they lived were included. The factors measured included HDL, living altitude, body mass index (BMI), smoking habits, alcohol consumption, diabetes, menopause in women, and physical activity and dietary habits. RESULTS: The HDL showed a correlation with living altitude (r = 0.14, P < 0.01) and with BMI (r = -0.19, P < 0.01). Smokers had lower HDL levels than ex-smokers and non-smokers (P < 0.05). Men who were moderate drinkers had higher HDL levels than heavy or mild drinkers and non-drinkers (P < 0.01). Physical activity was only related to HDL in men with levels >1.52 mmol/l, who walked on the average more than the rest (P < 0.05). Variables not showing the expected relationship with HDL were diabetes and the menopause in women (probably due to a low statistical power of their subsamples). Regression analysis, with HDL as dependent variable showed that the association between HDL and altitude persists when taking altitude as a categorical or a continuous variable. CONCLUSIONS: High density lipoprotein cholesterol levels are linearly and significantly increased when living at a higher altitude. This fact should be taken into account when comparing cardiovascular risk in populations living at different altitudes.

High density lipoprotein cholesterol is associated with serum cortisol in older people
Varma, V. K., J. T. Rushing, et al. (1995), J Am Geriatr Soc 43(12): 1345-9.
Abstract: OBJECTIVE: To determine the associations between serum cortisol and HDL cholesterol, other lipoprotein lipids and cardiovascular risk factors, carotid atherosclerosis, and clinical heart disease in older people. DESIGN: A cross-sectional, observational, ancillary study of the Cardiovascular Health Study (CHS). POPULATION: A total of 245 community-dwelling people, 65 to 89 years old, were recruited consecutively for a 2-month period from the CHS cohort in Forsyth County, North Carolina. METHODS: Cortisol was measured by radioimmunoassay in serum collected between 7:00 and 10:00 AM after an overnight fast. Cortisol levels were correlated with lipoprotein lipids, insulin, glucose, body mass index, waist-hip ratio, prevalent coronary heart disease, hypertension, diabetes, and carotid atherosclerosis by B-mode ultrasound. RESULTS: Serum cortisol was correlated negatively (r = -.24) with body mass index and waist-hip ratio (r = -.16) but was not related significantly to fasting insulin or glucose. Cortisol was not associated significantly with triglyceride and low density lipoprotein cholesterol but showed a positive correlation (r =.21) with high density lipoprotein cholesterol. The relationship between cortisol and high density lipoprotein cholesterol persisted after adjustment for gender, body mass index, waist-hip ratio, cigarette and alcohol use, triglyceride level, and diabetes. There was a trend toward a negative correlation between cortisol and measures of carotid atherosclerosis, but no significant relationship was indicated between cortisol and prevalent coronary heart disease, hypertension, or diabetes. CONCLUSION: Endogenous glucocorticoid levels correlated with HDL cholesterol levels and may play a role in the physiologic regulation of high density lipoprotein levels in older people.

High density lipoprotein cholesterol level in rats poisoned with cadmium
Skoczynska, A. (2001), Med Pr 52(5): 355-9.
Abstract: The effect of cadmium on lipid metabolism in persons occupationally and environmentally exposed to this metal may lead to the occurrence of cardiovascular diseases. The disturbances of the reverse transport of cholesterol could be responsible for the vascular changes. The aim of this study was to evaluate the impact of cadmium on the cholesterol level in the main fraction and subfractions of high density lipoprotein (HDL). The cholesterol level was measured in serum of rats treated with cadmium in a weekly dose of 5 mg/kg b.w. for seven weeks and in controls. After a seven-week exposure, the decreased HDL2, and the increased HDL3 cholesterol levels were observed in cadmium-poisoned animals as compared to controls. The results of the study suggest that a cadmium-impaired mechanism of the cholesterol transport in blood may induce vascular changes.

High density lipoprotein cholesterol low serum level as the only risk factor in male patients with coronary heart disease
Alessandri, C., S. Basili, et al. (1992), Clin Ter 141(8): 109-14.
Abstract: Forty-three male patients with myocardial infarction, severe angiographic coronary lesions, high or normal low density lipoprotein (LDL) cholesterol serum levels, and without other risk factors for coronary heart disease were selected. In all patients high density lipoprotein (HDL) cholesterol and HDL-cholesterol/total cholesterol ratio were significantly lower than in the control group; in particular, the ratio was below 0.240 which was the median value of normal subjects. Six patients with total cholesterol and LDL-cholesterol below 5.16 and 3.35 mmol/l respectively, had low serum levels of HDL-cholesterol; in 4 of them the value of this risk factor was below 0.9 mmol/l; 2 of 6 patients had a lipoprotein (a) serum concentration above 0.3 g/l but not a premature myocardial infarction or a clinical history of coronary heart disease. Our data confirm that HDL-cholesterol/total cholesterol ratio could be a better marker of coronary heart disease than HDL-cholesterol, total cholesterol or LDL-cholesterol and suggest the importance to check HDL-cholesterol serum levels also in subjects without risk factors for atherosclerotic disease.

High density lipoprotein cholesterol subfractions in older people
Ettinger, W. H., Jr., R. B. Verdery, et al. (1994), J Gerontol 49(3): M116-22.
Abstract: BACKGROUND. High density lipoprotein (HDL) may be an important risk factor for cardiovascular disease in older people. HDL is heterogeneous with several subfractions. This article describes the distribution and correlates of HDL2 cholesterol (C) and HDL3-C in older people. METHODS. HDL subfraction cholesterols were measured in 1,127 females and 825 males > or = 65 years old who participated in the Cardiovascular Health Study. Distributions of HDL subfraction cholesterols and bivariate and multivariate relationships were determined in cross-sectional analyses. RESULTS. Mean (+/- SD) concentrations of HDL subfractions were: HDL3-C (M.98 +/-.25, F 1.2 +/-.29 mmol/l), HDL2-C (M.09 +/-.08, F.13 +/-.09 mmol/l). HDL2-C, but not HDL3-C, was slightly higher with age. Using multivariate analysis, both HDL2-C and HDL3-C (in females) were inversely correlated with triglyceride, body weight, and fasting insulin; HDL3-C was inversely correlated with central fat distribution in women. Both HDL2-C and HDL3-C were lower in participants with prevalent cardiovascular disease. However, only HDL3-C was significantly inversely related to carotid stenosis, as measured by ultrasound. CONCLUSIONS. The slight increase in HDL-C with age appears to be due to an increase in the HDL2-C subfraction. HDL-C subfractions are independently related to triglyceride levels, body weight, and insulin concentrations in older people, all potentially modifiable risk factors. Both HDL2-C and HDL3-C are lower in older people with prevalent cardiovascular disease, although only HDL3-C was correlated with carotid atherosclerosis. These findings are consistent with the hypothesis that HDL subfractions are important risk factors for atherosclerotic cardiovascular disease in the elderly.

High density lipoprotein cholesterol. A 16-year longitudinal study in aging male twins
Christian, J. C., D. Carmelli, et al. (1990), Arteriosclerosis 10(6): 1020-5.
Abstract: The National Heart, Lung, and Blood Institute Twin Study is a collaborative, longitudinal study of white, male twins who were veterans of World War II and were born between 1917 and 1927. The twins were selected from the National Academy of Sciences/National Research Council Twin Panel and were examined three times (1969-73, 1981-82, and 1986-87). At all three exams, the dizygotic (DZ) twins were found to have a greater total variance for high density lipoprotein cholesterol (HDL-C) than the monozygotic (MZ) twins (p less than 0.05). DZ variance estimates were also larger than the variance of singletons from the second National Health and Nutrition Examination Survey. At the third exam, HDL-C was divided by precipitation into HDL2 and HDL3 fractions, and HDL2 was found to be the primary cause of the greater DZ total variance (DZ/MZ HDL2 variance = 2.22). The DZ/MZ variance ratio decreased 9% after adjustment of HDL2 for correlations with plasma triglycerides, alcohol consumption, smoking, exercise, and body mass index measured at the third exam. Postulated causes of the difference between MZ and DZ total variances include World War II induction screening, environmental influences unique to one zygosity, and genetic factors related to twinning. Further understanding of the etiology of this striking difference between MZ and DZ twin variance for HDL-C fractions could lead to more effective methods of decreasing the complications of arteriosclerosis.

High density lipoprotein composition in moscovites with low and high HDL cholesterol level
Ozerova, I. N., V. A. Metel'skaia, et al. (2001), Ter Arkh 73(9): 34-8.
Abstract: AIM: To elucidate if there are any peculiarities in HDL composition in Muscovites with different HDL C levels, and to reveal which HDL components could determine the disturbances in their antiatherogenic properties at higher HDL C level. MATERIAL AND METHODS: Sixty men aged 40-59 years with low HDL C level < 40 mg/dl (36 +/- 0.8 mg/dl; n = 30) and high HDL C level > 50 mg/dl(58 +/- 1.6 mg/dl; n = 30) were compared. Enzymatic, immunonephelometric methods and thin-layer chromatography were used. RESULTS: Men with high HDL C level had higher concentration of apo AI, HDL phospholipids (PL), ratios of HDL C/apo AI and HDL C/HDL PL but lower ratio of HDL C free/HDL PL. The analysis of HDL PL composition revealed in subjects with high HDL C higher proportion of phosphatidylcholine (PC) and lower lysoPC, whereas the relative content of sphingomyelin and phosphatidylethanolamine did not differ between the groups. CONCLUSION: The peculiarities in components of HDL found among men with different HDL C levels could explain less effective HDL atheroprotective properties in Muscovites with elevated HDL C.

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Cholesterol Journal Articles